\documentclass{article}
\usepackage[T2A]{fontenc}
\usepackage[cp1251]{inputenc}
\usepackage[english,bulgarian]{babel}
\usepackage{pifont}
\usepackage{pstricks}
\newpsstyle{gridstyle}{subgriddiv=0,gridcolor=lightgray,griddots=10,gridlabels=0pt}
\usepackage{pst-pdf}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows,calc}

\begin{document}

\begin{pspicture}[showgrid=false](0,0)(1,4.2)

% Define block styles

\tikzstyle{rec} = [rectangle, draw,fill=green!10, draw=green!75,thick,text width=14em,rounded corners, text badly centered, minimum height=2.5em]
\tikzstyle{line} = [draw, -latex']
\tikzstyle{back} = [rectangle, draw=black,thick,minimum height=7em,text width=14em,fill=gray!15]
\tikzstyle{del} = [draw=none,fill=none, inner sep=-8pt,outer sep=0pt, minimum size=2pt, node distance=6.3em,minimum height=0.1mm]


\pgfsetendarrow{\pgfarrowlargepointed{2.5pt}}

\begin{tikzpicture}[node distance = 2cm]

% Place nodes
    \node [rec,fill=blue!10, draw=blue!75,thick] (A) {Видове микропроцесори};
    \node [back, below left of=A,node distance=9em](B){};
    \node [rec, below right of=A, text width=8em, node distance=10em,fill=orange!10, draw=orange!75,thick] (C) {Универсални микропроцесори};
    \node [rec, below left of=A, text width=9em,minimum height=0.5em, node distance=2.2cm,fill=orange!10, draw=orange!75,thick] (D) {Вградени системи};
    \node [del, below left of=D, node distance=1.8cm] (del) {};
    \node [rec, right of=del, text width=5em, node distance=2cm] (F) {Сигнални процесори};
    \node [rec, left of=F, text width=7em, node distance=2.5cm] (E) {Микро-контролери};


% Draw edges
    \path [line,very thick] (A) -- (B);
    \path [line,very thick] (A) -- (C);



\end{tikzpicture}
\end{pspicture}

\end{document} 